HP OpenVMS Systems Documentation

OpenVMS User's Manual

Pressing the Backspace key moves the cursor backwards and erases the
character in that space.
If line editing is enabled, you can use Ctrl/U to delete characters
from the beginning of the line to the current cursor position. If line
editing is not enabled, you can use Ctrl/U to cancel an entire line.
The system ignores the line and redisplays the DCL prompt.

A key definition is a string of characters that you assign to a
particular terminal key. Use the DEFINE/KEY command. When a key is
defined, you can press it instead of typing the string of characters. A
key definition usually contains all or part of a command line. Using
key definitions, you can customize your keyboard so that you can enter
DCL commands with fewer keystrokes. When you press a defined key, the
system either displays the command on your terminal or executes the
command, depending on whether the command was defined using the
/TERMINATE qualifier.

By default, the terminal is set to numeric keypad mode. Use the SET
TERMINAL command to redefine the keys on the numeric keypad. For more
information, see the descriptions of the SET
TERMINAL/APPLICATION_KEYPAD, SET TERMINAL/NONUMERIC, and DEFINE/KEY
commands in the OpenVMS DCL Dictionary.

Momentarily interrupts terminal output to display a line of statistical
information about the current process. This display includes your node
and user name, the time, the name of the image you are running, and
information about system resources used during your current terminal
session.

You can also use Ctrl/T to determine whether the system is
operating. Ctrl/T does not Enter information if the system is
temporarily unresponsive or if your terminal is set to NOBROADCAST. To
use Ctrl/T, you must first enter the SET CONTROL=T command (in the
system login command procedure, in your personal login command
procedure, or interactively).

Ctrl/Y, Ctrl/C and F6

Interrupts command processing. You can disable Ctrl/Y with the command
SET NOCONTROL=Y.

Under most conditions, Ctrl/Y returns you to the DCL prompt. The
program running is still active. You can enter any built-in command
then continue the program with the CONTINUE command. (Press Ctrl/W to
refresh the screen after you enter the CONTINUE command.)

Switches between overstrike and insert mode. The default mode (as set
with the SET TERMINAL/LINE_EDITING command) is reset at the beginning
of each line.

Ctrl/D and left arrow

Moves the cursor one character to the left.

Ctrl/E

Moves the cursor to the end of the line.

Ctrl/F and right arrow

Moves the cursor one character to the right.

Ctrl/H and F12

Moves the cursor to the beginning of the line.

Ctrl/I and Tab

Moves the cursor to the next tab stop on the terminal. The system
provides tab stops at every eighth character position on a line. Tab
settings are hardware terminal characteristics that, in general, you
can modify. The Tab key also works when line editing is disabled.

Ctrl/J

Deletes the word to the left of the cursor.

Ctrl/K

Advances the current line to the next vertical tab stop.

Ctrl/L

Moves the cursor to the beginning of the next page. This use of Ctrl/L
is ignored when line editing is enabled.

Ctrl/R

Repeats the current command line and leaves the cursor positioned where
it was when you pressed Ctrl/R.

Ctrl/U

Deletes all text in the current input line that is to the left of the
cursor.

Ctrl/V

Turns off some of the line editing function keys. For example, if you
press Ctrl/V followed by Ctrl/D, a Ctrl/D is generated instead of the
cursor moving left one character. Ctrl/D is a line terminator at DCL
level.

When combined with Ctrl/V, characters that are not line terminators
have no effect. Examples are Ctrl/H and Ctrl/J. However, certain
control keys, such as Ctrl/U, retain their line editing functions.

A file is a system object that contains information.
This information can be machine-readable data that the
computer understands. It can also be text that you enter and
manipulate. The contents of a file might be the text of a document, a
program, or a list of addresses. You can examine the contents of a text
file by displaying it online or by printing it.

A program, also called an image or an
executable image, is a file that contains instructions
and data in machine-readable format. Some programs are associated with
a DCL command. For example, when you type the DCL command COPY, the
system runs the program SYS$SYSTEM:COPY.EXE. Some programs are started
by entering the DCL command RUN followed by the program name.

Image files can be supplied by the operating system or by you and
usually have the file type .EXE. You cannot examine an image file with
the DCL commands TYPE, PRINT, or EDIT because image files do not
consist of ASCII characters. (Text files contain ASCII
characters, which are a standard method of representing the alphabet,
punctuation marks, numerals, and other special symbols.)

This chapter describes how to create and manipulate files locally, and
over a TCP/IP or DECnet for OpenVMS network. It includes information
about:

Understanding file names and file specifications

Using wildcards with file names

Other file names

Creating and modifying files

Displaying the contents of files

Deleting files

Protecting files from other users

Printing files

For additional information, refer to the following:

Chapter 5, for information about file names in an environment
using extended file specifications

The OpenVMS DCL Dictionary and online help, for commands discussed in this
chapter

The OpenVMS System Manager's Manual, for information about accessing remote nodes

The Compaq TCP/IP Services for OpenVMS User's Guide, for
information about using TCP/IP user utilities and commands

The DECnet for OpenVMS Networking Manual, for information about DECnet networks

The DECnet-Plus for OpenVMS Introduction and User's Guide,
for information about DECnet Phase V networks

A file is a unit that the OpenVMS operating system uses to store
human-readable and machine-readable data. When you create or name a
file, you provide information the system can use to locate and identify
the file.

A filename consists of a file name
and a file type. The name and type are separated by a
period (.). A file also has a version number. You can
have several versions of a file. Unless you specify a version number,
the system uses the highest existing version number of a file. When you
edit a file, the system does not modify the original version, but
creates a new output file. By default, the output file
has the same name and file type as the original, but has a version
number that is one higher than the existing file(s) of the same name.

The file name, file type, and version number form a file
specification.

A file is located on a specific computer (or node) in the network, on a
specific device or set of devices (known as a volume) connected to that
computer, in a particular directory on that volume. A complete file
specification:

Precisely describes the access path the system uses to locate and
identify a file

Can include the directory in which the file is located and the
network node on which the file resides

Is also known as a network file specification

You do not have to include all the elements of a complete file
specification. However, you must specify enough of the file
specification so that, when combined with default components, the
system can locate and identify the correct file.1

To override system defaults or to perform file operations over a
network, you must provide a complete file specification. A complete
file specification has the following format:

node::device:[root.][directory]file-name.file-type;version

The components are as follows:

Node

A network node or host name; applicable only to systems that support
TCP/IP or DECnet. Does not apply to files stored on magnetic tape.
Should not be used to specify a file on the same system that you are
logged in to.

Device

The term used to refer to a disk or tape drive or other peripheral
connected to a computer running the OpenVMS operating system. Each
device has a unique name that indicates its type and location. Disks
can be formatted as ODS-2 (the default) or ODS-5 (OpenVMS Alpha only).

Directory

The name of the directory in which a file is stored. Square brackets
([]) or angle brackets (<>) are used to delimit directories. Does
not apply to files stored on magnetic tape.

File name

The name of the file.

File type

Identifies the structure or the type of the file.

Version

The version number of the file. Versions are identified by a decimal
number, which is incremented by 1 each time a new version of the file
is created. The system automatically assigns a version number unless
you specify one.

Use the following rules to specify the elements of a file specification:

Give the file a name that is meaningful to you. On OpenVMS Alpha
and OpenVMS VAX systems with ODS-2 disks, the file name can have up to
39 characters chosen from the letters A to Z (uppercase or lowercase),
the numbers 0 to 9, underscores (_), hyphens (-), tildes (~), and
dollar signs ($).

Do not use a hyphen as the first character in the file name because
some older versions of OpenVMS do not allow it in all forms of a file
specification.

The file type begins with a period (.). On Alpha and VAX systems
with ODS-2 disks, the file type can have up to 39 characters (including
the period), chosen from the letters A through Z (which may be
specified in uppercase or lowercase form), the numbers 0 through 9,
underscores (_), hyphens (-), and dollar signs ($).

A version component begins with a semicolon (;) or a period (.)
When the system displays file specifications, it displays a semicolon
for the version component.

Do not use a directory field to refer to files on magnetic tape.
(Directories apply only to files on disks.)

Include a node name only if your system is part of a network and if
the file is on a node other than the one you are logged in to.

On OpenVMS Alpha and OpenVMS VAX systems with ODS-2 disks, a UFD
(User File Directory) name or a subdirectory name can be 39 characters
long and can contain characters chosen from the letters A through Z
(which may be specified in uppercase or lowercase form), the numbers 0
through 9, underscores (_), hyphens (-), and dollar signs ($). A
subdirectory name beginning with a hyphen is not allowed.

On OpenVMS Alpha Version 7.2 or later, the sum of the numbers of
characters in all of the subdirectories of the directory and root
components (not including brackets and separator periods) should not
exceed 512. In addition, UFD and subdirectory names have the same
constraints as those for the file name, type, and version components,
taking into account the fact that directories are stored as files of
the form <directory-name>.DIR;1.

In environments that consist of systems that support extended file
specifications and systems that do not, remember that files and
directories whose names are beyond the capabilities of the more limited
systems will not be accessible from those systems.

For more details, refer to the Guide to OpenVMS File
Applications.

Note

Note that these rules differ for files in an environment with extended
file specifications. Refer to Chapter 5 for more specific
information about extended file names.

Input source file for the VAX MACRO assembler or the MACRO-32 Compiler
for OpenVMS Alpha

.MLB

Macro library for the MACRO assembler

.MSG

Source file that specifies the text of messages

.OBJ

Object file created by a language compiler or assembler

.OLB

Object module library

.OPT

Options file for input to the LINK command

.PAS

Input source file for the Pascal compiler

.PLI

Input source file for the PL/I compiler

.STB

Symbol table file created by the Linker utility

.UPD

Update file of changes for a VAX MACRO source program; also input to
the SUMSLP utility

Note

1 Record Management Services (RMS) is
the OpenVMS facility that assists application programs in processing
and managing files. RMS maintains the rules for file specification
parsing. Refer to the Guide to OpenVMS File Applications for
more information on how RMS applies defaults to partial file
specifications.